Subject: Re: [linux-audio-user] MIDI question
From: Robert Jonsson (robert.jonsson_AT_dataductus.se)
Date: Thu Mar 14 2002 - 14:40:37 EET
> why should anyone have problems with a midi sequencer on a pentium 200? that
> should be more than enough for midi applications. i've benn running midi
> sequencers since 1987, first on an old atari st1040 (8Mhz and 1 Mb ram), then
> on a 486 and later on on a pentium 133. always with perfect timing and using
> sequencers more complex and with many more features than muse has now. (it's
> true that i had a real midi card, something that seems to be rather rare now.)
> i agree with gavin, that a pentium 200 should be adequate for working with
> digital audio, and more than enough for any midi application.
It's essentially multitasking, or rather lack of good multitasking that causes
this to be an issue.
Your atari and old pc's was not running a real multitasking os. This makes
timing alot easier. These days you have to take necessary precautions to be
certain that the sequencer can stay in sync.
Your sequencer app is not the only one using the system, atleast the sequencer
cannot (easily) make that assumption.
For Linux there is the SCHED_FIFO architectural "loophole". It's a way of making
sure that your app gets to run atleast once every iteration (and as long as it
likes) the operating system does. But... since there isn't 100% certainty the OS
will will complete a roundtrip within a certain TIMEOUT, it isn't perfect.
Performance is more stable with more powerful computers though.
With the lowlatency patches that are the buzz of the day things improve greatly.
Basically we can say that the reason you cannot run your run of the mill
sequencer on any computer is because of multitasking imperfection.
Things will surely improve but the rock steadiness of DOS will be hard to
achieve. On the otherhand, computers of today or much much much more versatile.
Another reason is trouble to use a (rather low resolution) timer in a
multitasking environment. Requires some work to behave correctly, but it can be
0.01 euros worth
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